Method and apparatus for steering traffic between cellular network and wireless local area network (LAN) network in mobile communication system

ABSTRACT

The present disclosure relates to a 5G or pre-5G communication system to be provided for supporting a higher data transmission rate beyond 4G communication systems such as LTE. More specifically, a method for transmitting and receiving signals by a base station of a mobile communication system according to one embodiment of the present specification comprises: a step of determining whether to steer a traffic related to a terminal to a wireless LAN; a step for determining a traffic to be steered to the wireless LAN; a step for transmitting, to the terminal, a first message including information for an uplink transmission of the traffic to be steered; and a step for transmitting, to a gateway, a second message including information for a downlink transmission of the traffic to be steered. According to an embodiment of the present specification, in a network and a terminal using both a cellular and a wireless LAN, presented is a method for transferring, via an access network considering the signal strength between the terminal and each access network, a load condition of each access network, a policy of a provider etc., traffic which are sent and received by the terminal and the network.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of Ser. No. 15/301,373, which is theNational Stage of International Application No. PCT/KR2015/003311, filedApr. 2, 2015, which claims priority to Korean Patent Application No.10-2014-0039371, filed Apr. 2, 2014, the disclosures of which are hereinincorporated by reference in their entirety.

BACKGROUND 1. Field

Embodiments of the present disclosure relate to a method and apparatusfor setting a traffic path in a wireless communication network. Moreparticularly, in a terminal which accesses a network through a cellularbase station and a wireless LAN (WLAN), embodiments relate to anapparatus and method for steering all or part of traffic, exchangedbetween the terminal and the network, from the cellular to the WLAN orvice versa.

2. Description of Related Art

In order to satisfy increasing demands of radio data traffic after thecommercialization of a 4G communication system, much effort is made todevelop an advanced 5G communication system or a pre-5G communicationsystem. For this reason, the 5G communication system or the pre-5Gcommunication system is also referred to as a beyond-4G networkcommunication system or a post-LTE system.

In order to accomplish a higher data transfer rate, the 5G communicationsystem considers implementation at a super-high frequency (mmWave) band(e.g., such as a 60 GHz band). In order to obviate a path loss of aradio wave and to increase a delivery distance of a radio wave at thesuper-high frequency band, various techniques such as a beamforming, amassive MIMO, a full dimensional MIMO (FD-MIMO), an array antenna, ananalog beam-forming, and a large scale antenna are discussed in the 5Gcommunication system.

Additionally, for an improvement in network of the 5G communicationsystem, technical developments are made in an advanced small cell, acloud radio access network (cloud RAN), an ultra-dense network, a deviceto device (D2D) communication, a wireless backhaul, a moving network, acooperative communication, coordinated multi-points (CoMP), a receptioninterference cancellation, and the like.

Besides, in the 5G communication system, a hybrid FSK and QAM modulation(FQAM) and a sliding window superposition coding (SWSC) are developed asadvanced coding modulation (ACM) schemes, and a filter bank multicarrier (FBMC), a non orthogonal multiple access (NOMA), and a sparsecode multiple access (SCMA) are also developed as advanced accesstechniques.

In addition, according to the explosive growth of mobile traffic, a WLANnetwork that can be constructed at a low cost by using an unlicensedband is being reviewed as a strong offloading solution of a cellularoperator which reaches the limit in handling traffic with only acellular network. Most cellular operators construct a WLAN networkthemselves or cooperate with the existing WLAN operators and, ifcellular base stations are incapable of handling subscribers' traffic ina crowded area, induce subscribers to be served through a wireless LANaccess point.

The 3GPP standard adopts a structure in which both the cellular networkand the WLAN access network are interworked at a gateway (PDN-GW) of acellular core network such that a terminal can be continually servedeven in case of handover between the cellular network and the WLANnetwork. In this structure, even though handover is made between thecellular network and the WLAN, the terminal may not suffer disconnectionof a service by maintaining the same IP address.

Therefore, a method and apparatus for selecting a transfer path oftraffic for effectively delivering traffic in this system and therebydetermining a traffic path are needed.

SUMMARY

Embodiments of the present disclosure are proposed to solve theabove-discussed problems and have an object of providing an effectivetraffic steering method and apparatus for a terminal that transmits andreceives data to and from a network through a cellular base station anda WLAN. Another object is to provide a method and apparatus foradjusting a network load by steering traffic, being offered througheither a cellular network or a WLAN network, to the other network.

In order to accomplish the above objects, a method for transmitting andreceiving a signal at a base station in a mobile communication systemaccording to an embodiment of this disclosure comprises steps of:determining whether to steer a traffic related to a terminal to awireless LAN (WLAN); determining the traffic to be steered to the WLAN;transmitting, to the terminal, a first message comprising information onuplink transmission of the traffic to be steered; and transmitting, to agateway, a second message comprising information on downlinktransmission of the traffic to be steered.

A method for transmitting and receiving a signal at a terminal in amobile communication system according to another embodiment of thisdisclosure comprising steps of: transmitting and receiving a traffic toand from at least one of a base station and a wireless LAN (WLAN);receiving, from the base station, a first message comprising informationon steering a part of the traffic; and steering the traffic, based onthe first message.

A base station in a mobile communication system according to anotherembodiment of this disclosure comprises a transceiver unit configured totransmit or receive a signal; and a controller configured to determinewhether to steer a traffic related to a terminal to a wireless LAN(WLAN), and to determine the traffic to be steered to the WLAN, whereinthe controller is further configured to control the transceiver unit totransmit, to the terminal, a first message comprising information onuplink transmission of the traffic to be steered, and to transmit, to agateway, a second message comprising information on downlinktransmission of the traffic to be steered.

A terminal in a mobile communication system according to still anotherembodiment of this disclosure comprises a transceiver unit configured totransmit or receive a signal; and a controller configured to control thetransceiver unit to transmit and receive a traffic to and from at leastone of a base station and a wireless LAN (WLAN), to receive, from thebase station, a first message comprising information on steering a partof the traffic, and to steer the traffic, based on the first message.

According to embodiments of the present disclosure, proposed is a methodfor delivering traffic, exchanged between a network and a terminal usingboth a cellular and a WLAN, through an access network in view of signalstrength between the terminal and each access, a load condition of eachaccess network, an operator's policy, and the like. Also, according toembodiments of this disclosure, a user of the terminal can use theoptimal access network proposed by the network and thereby keep the bestuser experience without undergoing any network congestion. And also,according to embodiments of this disclosure, a network operator canminimize a network operating cost by properly distributing traffic onthe basis of one of a load condition of the access network and a policythereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a network structure according to anembodiment of the present disclosure.

FIG. 2 is a diagram illustrating a structure of a communication systemaccording to an embodiment of the present disclosure.

FIG. 3 is a diagram illustrating a method for delivering trafficaccording to an embodiment of the present disclosure.

FIG. 4 illustrates a parameter for setting a WLAN preference of a beareraccording to an embodiment of the present disclosure.

FIG. 5 illustrates another parameter for setting a WLAN preference of abearer according to an embodiment of the present disclosure.

FIG. 6 illustrates still another parameter for setting a WLAN preferenceof a bearer according to an embodiment of the present disclosure.

FIG. 7 is a diagram illustrating a method for setting a bearer at agateway according to an embodiment of the present disclosure. In anembodiment, the gateway may include a PGW.

FIG. 8 illustrates a method for acquiring, at a PGW, locationinformation about a terminal according to an embodiment.

FIG. 9 illustrates another method for acquiring, at a PGW, locationinformation about a terminal according to an embodiment.

FIG. 10 illustrates a method for checking, at a base station, whether aWLAN accepts traffic.

FIG. 11 illustrates a method for returning, at a base station, traffictransmitted to a WLAN to a base station according to an embodiment.

FIG. 12 illustrates a method for transferring a bearer serviced by abase station to a WLAN according to an embodiment of this disclosure.

FIG. 13 illustrates a method for steering traffic at a terminalaccording to an embodiment.

FIG. 14 illustrates a method for transferring a bearer serviced by aWLAN to a base station according to an embodiment of this disclosure.

FIG. 15 is a diagram illustrating a terminal according to an embodiment.

FIG. 16 is a diagram illustrating a WLAN according to an embodiment.

FIG. 17 is a diagram illustrating a base station according to anembodiment.

FIG. 18 is a diagram illustrating a PGW according to an embodiment.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention will be described withreference to the accompanying drawings.

In this disclosure, some techniques or elements, which are well known inthe art or irrelevant to disclosed embodiments, may not be described orillustrated in detail. This is to avoid obscuring the subject matter ofthe present disclosure.

For similar reasons, the drawings are not necessarily to scale andcertain features may be exaggerated or omitted in order to betterillustrate and explain the present disclosure. Through the drawings, thesame or similar reference numerals denote corresponding featuresconsistently.

The present invention may be embodied in many different forms and shouldnot be construed as limited to the embodiments set forth herein. Rather,the disclosed embodiments are provided so that this disclosure will bethorough and complete, and will fully convey the scope of this inventionto those skilled in the art. The principles and features of the presentinvention may be employed in varied and numerous embodiments withoutdeparting from the scope of the invention. Accordingly, it should beapparent to those skilled in the art that this description is providedfor illustration purpose only and not for the purpose of limiting thepresent invention as defined by the appended claims and theirequivalents.

It will be understood that each block of the flowchart illustrations,and combinations of blocks in the flowchart illustrations, can beimplemented by computer program instructions. These computer programinstructions can be provided to a processor of a general purposecomputer, special purpose computer, or other programmable dataprocessing apparatus to produce a machine, such that the instructions,which are executed via the processor of the computer or otherprogrammable data processing apparatus, create means for implementingthe functions specified in the flowchart block or blocks. These computerprogram instructions may also be stored in a computer usable orcomputer-readable memory that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer usable orcomputer-readable memory produce an article of manufacture includinginstruction means that implement the function specified in the flowchartblock or blocks. The computer program instructions may also be loadedonto a computer or other programmable data processing apparatus to causea series of operational steps to be performed on the computer or otherprogrammable apparatus to produce a computer implemented process suchthat the instructions that are executed on the computer or otherprogrammable apparatus provide steps for implementing the functionsspecified in the flowchart block or blocks.

And each block of the flowchart illustrations may represent a module,segment, or portion of code, which comprises one or more executableinstructions for implementing the specified logical function(s). Itshould also be noted that in some alternative implementations, thefunctions noted in the blocks may occur out of the order. For example,two blocks shown in succession may in fact be executed substantiallyconcurrently or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved.

The term “unit”, as used herein, may refer to a software or hardwarecomponent or device, such as a Field Programmable Gate Array (FPGA) orApplication Specific Integrated Circuit (ASIC), which performs certaintasks. A unit may be configured to reside on an addressable storagemedium and configured to execute on one or more processors. Thus, amodule or unit may include, by way of example, components, such assoftware components, object-oriented software components, classcomponents and task components, processes, functions, attributes,procedures, subroutines, segments of program code, drivers, firmware,microcode, circuitry, data, databases, data structures, tables, arrays,and variables. The functionality provided for in the components andmodules/units may be combined into fewer components and modules/units orfurther separated into additional components and modules.

Hereinafter, embodiments of the present disclosure will be describedwith reference to the accompanying drawings. In this disclosure, wellknown functions or structures may not be described or illustrated indetail to avoid obscuring the subject matter of the present invention.

An embodiment of the present disclosure relates to an apparatus andmethod for steering, from a cellular to a WLAN or vice versa, all orpart of traffic transmitted under the control of a network in acommunication between the network and a terminal using both the cellularand the WLAN.

An embodiment of this disclosure may include technical features asfollows.

(1) Bearer setting in view of WLAN preference for each traffic

In a traffic steering method according to an embodiment of thisdisclosure, a cellular base station (or referred to as a base station)may determine whether to steer traffic and also determine a steeringdirection. Specifically, the base station can know best a resourcecondition of a real-time radio access and thus make a decision relatedto a radio access.

However, the base station may not distinguish a PDN or a flow andinstead allow identifying in a bearer unit. Specifically, in anembodiment, the base station may perform a control in a bearer unit, notin a flow unit, in connection with traffic being transmitted.

Disclosed in an embodiment of this disclosure is a method fordetermining a WLAN preference of traffic by considering one or more ofthe location of a terminal that receives traffic from a gateway, a PDNthat transmits traffic. QCI corresponding to traffic, and a flow type oftraffic, and then delivering traffic having WLAN preference values beingequal, similar, or within a specific range by means of a single bearer.In an embodiment, a WLAN preference that determines priority fortransmission to WLAN of traffic contained in a bearer may have a valuewithin a specific range, e.g., from 0 to 255. In an embodiment, the basestation may determine traffic to be steered preferentially on the basisof such a WLAN preference value.

(2) Check traffic capability of WLAN

When the terminal transmits and receives data through the WLAN, theterminal needs to be offered QoS being similar in level to that offeredthrough the cellular. In this case, the cellular base station and theWLAN AP are required to exchange information about which level oftraffic is desired or can be delivered.

For the above, disclosed in an embodiment is a procedure in which thecellular base station checks, through the terminal, whether the WLAN APcan accept traffic to be steered by the cellular. Specifically, theterminal may request information related to a transmission capacity ofthe WLAN AP at the request of the base station. Also, the terminal maydeliver transmission capacity information, received from the WLAN AP, tothe base station.

(3) QoS monitoring of bearer transferred to WLAN

Normally the WLAN using an unlicensed band has always a possibility ofQoS degradation due to external interference or the like. Therefore, anembodiment of this disclosure includes a method for returning traffic tothe cellular in case traffic transmitted via the WLAN has degraded QoS.Also, the base station may monitor, through the terminal, QoS of traffictransmitted via the WLAN, and based on a monitoring result, return suchtraffic to the cellular.

(4) Bearer resetting initiated by cellular base station

In an embodiment of this disclosure, the cellular base station maydetermine to transfer a specific bearer from the cellular to the WLAN orvice versa in view of a resource condition of a radio access network.For this, an embodiment includes a procedure in which the cellular basestation resets a bearer among the terminal, the access network, and thecore network gateway.

In an embodiment, the determination of steering traffic from the WLAN tothe cellular network or vice versa may be performed by at least one ofthe base station, the WLAN AP, and a network node. This network node maybe at least one of PGW and SGW. Hereafter, an embodiment of thisdisclosure will be described in detail with reference to drawings.

FIG. 1 is a diagram illustrating a network structure according to anembodiment of the present disclosure.

Referring to FIG. 1, user equipment (UE) 110, also referred as aterminal herein, is connected with a PDN gateway (PGW) 140 through a3GPP access network 120 including a serving gateway (SGW) 130 or througha wireless LAN (WLAN) 150, and may transmit or receive data to or froman internet 170. A policy and related information on transmission andreception of data between different networks may be received through anaccess network discovery service function (ANDSF) 160.

In an embodiment, the 3GPP Access network 120 may include a base station(also referred to as evolved nodeB (eNB) herein).

The internet 170 may include a plurality of PDNs, and the PDN and the UE110 may transmit or receive data to or from each other.

It may be needed to determine whether to transmit traffic, transmittedor received by the UE, through the 3GPP access network 120 or throughthe WLAN 150. Therefore, in an embodiment, a method and apparatus fortransferring specific traffic on the basis of such determination aredisclosed.

Additionally, in an embodiment, the WLAN 150 may be connected with the3GPP access network 120.

In an embodiment, the WLAN 150 may be directly connected with the 3GPPaccess network 120. For example, the WLAN 150 operated by an operator ofthe 3GPP access network 120 may be directly connected with the 3GPPaccess network 120.

In another embodiment, the WLAN 150 may be connected with the 3GPPaccess network 120 through a separate node. This separate node may be agateway related to security, for example, an evolved packet data gateway(ePDG).

If the WLAN 150 is directly connected with the 3GPP access network 120as discussed above, the WLAN 150 may receive a signal from the SGW 130.Also, when it is determined to perform traffic steering, the SGW 130 mayperform traffic steering toward the 3GPP access network 120 or the WLAN150.

FIG. 2 is a diagram illustrating a structure of a communication systemaccording to an embodiment of the present disclosure.

Referring to FIG. 2, whether UE 205 transmits and receives data via WLAN215 generally complies with a rule (or policy) predefined in the UE 205or a rule received from an ANDSF server. However, if the state of the3GPP access network (2G/3G or LTE) is considered in case of trafficoffloading toward the WLAN 215, or in order to perform a control oftraffic offloading more dynamically, a method of commanding at eNB 210as follows may be used.

Namely, the eNB 210 may command the UE 205 to report the state (signalstrength, a congestion status, a connection status, etc.) of theneighboring WLAN 215, collect related information, and then instructboth the UE 205 and the network to offload specific traffic toward theWLAN 215 in consideration for both the collected information and thestate of the eNB 205. Also, according to an embodiment, such specifictraffic to be offloaded may be determined on the basis of a specificparameter contained in a bearer. And also, in an embodiment, thespecific parameter may include a WLAN preference.

FIG. 3 is a diagram illustrating a method for delivering trafficaccording to an embodiment of the present disclosure.

Referring to FIG. 3, UE 310 may receive downlink traffic 340 from a PGW330 through a RAN 320. In an embodiment, the RAN may include at leastone of eNB 322 and a WLAN 323.

The first traffic 342 transmitted through the eNB 322 may include thefirst bearer to the fourth bearer. Also, the second traffic 344transmitted through the WLAN 323 may include the fifth bearer. Thenumber of bearers being transmitted may be varied according toembodiments.

In an embodiment, the UE 310 is attached to an operator's network thatsimultaneously services both a cellular and a WLAN, and issimultaneously connected with both the eNB (i.e., a cellular basestation) 322 and the WLAN AP 323. Additionally, based on the WLANinterworking standard of 3GPP, a network operator connect (anchoring) a3GPP cellular network and a non-3GPP WLAN at the PGW 330. Additionally,according to an embodiment, in case the WLAN is directly connected withthe 3GPP access network, an SGW may connect the 3GPP cellular networkand the non-3GPP WLAN.

In an embodiment of this disclosure, the eNB 322 may determine,depending on resource conditions of the access network, whether tocontinuously serve a specific bearer through the eNB 322 or to serve thebearer after steering toward the WLAN AP 323.

In this process, based on a WLAN preference specified in a bearer, theeNB 322 may determine such a specific bearer to be steered.

In an embodiment, a plurality of bearers may be set between the accessnetwork and the gateway of the core network. Each bearer may include aWLAN preference value.

For example, the minimum value (e.g., 0) of a WLAN preference means thatan operator does not want to serve such traffic to the WLAN. Therefore,the eNB does not instruct steering toward the WLAN with regard to abearer having zero as a WLAN preference value. On the contrary, themaximum value (e.g., 255) of a WLAN preference means that an operatorwants to serve such traffic to the WLAN if possible. Therefore, if theUE is connected with the WLAN AP, a relevant bearer is always served tothe WLAN AP. The above values of a WLAN preference are exemplary onlyand may have any other range. Additionally, in an embodiment, the eNB322 may perform traffic steering on the basis of a WLAN preferencevalue. Specifically, traffic having a higher WLAN preference value maybe preferentially steered to the WLAN 323.

In an embodiment, a target of dynamic steering based on resourceconditions of the access network detected by the eNB 322 may have acertain WLAN preference value which falls between the minimum value andthe maximum value. For example, if the UE 310 is simultaneouslyconnected with both the eNB 322 and the WLAN AP 323, and if the eNB 322has a higher transmission load since traffic of the eNB 322 is greaterthan that of the WLAN AP 323, the eNB 322 may determine to steer all orpart of traffic, transmitted or received to or from the UE 310, towardthe WLAN AP 323.

In an embodiment, if the eNB 322 determines to steer part of traffic ofthe UE 310, the eNB 322 may consider preferentially steering traffichaving a high WLAN preference with reference to a WLAN preference valueof a bearer. Although in an embodiment the PGW sets a WLAN preferencevalue, any other entity of any other network may set a WLAN preferencevalue.

Meanwhile, an embodiment exemplarily shows a setting state of a bearerat a specific moment. The PGW 330 serves traffic through five bearers inview of PDN, QCI, flow type, and the like, and each bearer has a WLANpreference value. A bearer 1 having a WLAN preference value of 0(minimum value) is served via the cellular network, and a bearer 5having a WLAN preference value of 255 (maximum value) is served via theWLAN network.

Meanwhile, in case of bearers 2, 3, and 4 having WLAN preference valuesbetween 0 and 255, these bearers are initially set to pass through thecellular network. However, depending on determination of the eNB, thesebearers may be dynamically steered between the cellular network and theWLAN network.

In this embodiment, since types of WLAN preference values are smaller innumber than the number of creatable bearers, different bearers may becreated for all WLAN preference values. However, if types of WLANpreference values are greater in number than the number of creatablebearers, it is possible to match some adjacent WLAN preference values toa single bearer.

FIG. 4 illustrates a parameter for setting a WLAN preference of a beareraccording to an embodiment of the present disclosure. Specifically, aparameter used for determining a WLAN preference according to a PDN typein a process of setting a WLAN preference of a bearer at a PGW isincluded.

Referring to FIG. 4, traffic being transmitted may have a type 402 ofPDN connected thereto. Each PDN type 402 has an exemplary service 404,and may have a preset WLAN preference.

In an embodiment, the PDN type may have at least one of an internet PDN,an operator PDN, and an IP multimedia subsystem (IMS).

In an embodiment, the internet PDN may have a TCP-based service, and theWLAN preference of the internet PDN may have a value of 200. However,any WLAN preference value used in this embodiment and followingembodiments is an exemplary only and may be set differently depending onimplementation.

In an embodiment, the operator PDN may include PDN for a richcommunication service, and the WLAN preference of the operator PDN has avalue of 50.

In an embodiment, the IMS PDN may include PDN for VoLTE, and the WLANpreference of the IMS PDN has a value of 0. Specifically, in anembodiment, data transmitted or received to or from the IMS PDN is notsteered toward the WLAN and instead transmitted or received through theeNB.

In this embodiment, the UE uses three PDN connections in total. In caseof the IMS PDN used for a service such as VoLTE, the disconnection ofservice may happen when the service is performed through a WLAN havingsmaller cell coverage. Therefore, an operator may set the WLANpreference of a bearer belonging to the IMS PDN at 0.

In case of offering a rich communication service or the like with aseparate operator PDN, an operator may set the WLAN preference value at50 which is slightly higher than that that of VoLTE.

In case of the internet PDN that serves normal internet traffic, anoperator may set the WLAN preference value at 200 which is a highervalue for promoting the utilization of WLAN.

FIG. 5 illustrates another parameter for setting a WLAN preference of abearer according to an embodiment of the present disclosure.Specifically, this shows an example of referring to QCI of a bearer whenthe PGW sets a WLAN preference of a bearer.

Referring to FIG. 5, traffic being transmitted may have QCI 502. EachQCI may have a resource type 504 and include an exemplary service 506.Therefore, each QCI may have a WLAN preference value 508.

In an embodiment, the QCI 502 may have values of 1 to 9. Therefore, theresource type 504 may include a guaranteed bit rate (GBR) and a non-GBR.

Additionally, each QCI 502 may include the exemplary service 506.

Like this embodiment, 3GPP defines nine types of QCIs. In an embodiment,in case of QCIs 5, 8, and 9 which mainly carry a service, such as IMSSignaling or default bearer, requiring a seamless connection, anoperator may set the WLAN preference at a value of 0 so as to be alwaysserviced through the cellular network. Additionally, in case of QCIs 1,2, 3, and 4 which have the resource type of GBR, an operator may set theWLAN preference at a lower value between 10 and 50 in view of thecharacteristics of the WLAN incapable of strict QoS guarantee due toexternal interference or the like.

Meanwhile, in case of QCIs 6 and 7 having the resource type of non-GBRand having certain tolerance of QoS degradation, an operator may set theWLAN preference at a relatively higher value.

As discussed heretofore in an embodiment, the PGW may set the WLANpreference on the basis of a QCI value.

FIG. 6 illustrates still another parameter for setting a WLAN preferenceof a bearer according to an embodiment of the present disclosure.

Referring to FIG. 6, in an embodiment, the PGW may determine a WLANpreference 608, based on at least one of a flow type 602 of trafficbeing transmitted, a UE location 604, and a time of day 606.

In an embodiment, the PGW may set the WLAN preference of a bearer on thebasis of the type of an IP flow type.

In an embodiment, the flow type 602 is 5-Tuple formed of a source IPaddress, a destination IP address, a source port number, a destinationport number, and a protocol identifier. In an embodiment, the PGW maydetermine the WLAN preference on the basis of at least one of pieces ofinformation contained in the flow type 602. Specifically, through suchinformation, an IP flow to which the WLAN preference will be assignedmay be distinguished from the others.

For example, with regard to SIP traffic filtered with (*, UE IP, SIP, *,UDP), an operator may set the WLAN preference at a value of 0 to bealways serviced via the cellular. Additionally, with regard to P2Ptraffic filtered with (*, UE IP, P2P, *, *), the WLAN preference may beset at a value of 255 to be always serviced via the WLAN.

In an embodiment, UE IP, SIP, P2P, etc. used in the above 5-Tuple aremerely convenient marks for easy understanding. Actually, real portnumbers used in applications of UE IP, SIP and P2P may be used insteadand, based on one or more of them, the WLAN preference may bedetermined.

Meanwhile, even regarding the same IP flows, an operator may appointdifferent WLAN preferences on the basis of at least one of the UElocation and the time of day.

In an embodiment, the UE location 604 allows different policies to becarried out depending on the location of UE. For example, an IP flowfiltered with (*, UE IP, *, *, *) may have different WLAN preferences ata particular place (Station XX in this embodiment) and the other places.In this example, Station XX is only exemplary only, and at least oneidentifier selected from ECGI, TAI, RAI, SAL, LAI, CGI, SSID, BSSID, andHESSID may be used as actual marks for location information.

Additionally, the time of day 606 in Table allows different policies tobe expressed depending on a time of day. For example, an IP flowfiltered with (*, UE IP, *, *, *) may have a higher WLAN preferencevalue of 40 at a time zone 11:00˜14:00 having heavier traffic incompared with a value of 10 at the other time zone. This higher WLANpreference value may promote the use of the WLAN.

As discussed heretofore in this embodiment, the eNB may determine a WLANpreference value on the basis of at least one type of informationselected from the flow type, the UE location, and the time of day.

FIG. 7 is a diagram illustrating a method for setting a bearer at agateway according to an embodiment of the present disclosure. In anembodiment, the gateway may include a PGW.

Referring to FIG. 7, at step 702, the gateway may receive one or more IPflows from a PDN.

At step 704, the gateway may apply an IP packet filtering to thereceived IP flow. Specifically, the gateway may perform a packetfiltering by applying a service data flow (SDF) template.

At step 706, the gateway may determine and enforce QoS for each SDF towhich a template is applied.

At step 708, the gateway may apply a traffic steering to each SDF.Specifically, at step 708, based on at least one of a UE location toreceive the SDF, a current time, a feature of IP flow, and QoS, thegateway may determine a mapping relation between a relevant flow and acertain bearer having a particular WLAN preference. Specifically, thegateway may set a bearer such that an SDF to be steered preferentiallyto the WLAN among IP flows can be mapped to a bearer having a higherWLAN preference. Specifically, if necessary, the gateway may create adedicated bearer and then map an SDF to that.

Further, the gateway may map some SDFs steered to the WLAN at similarpriorities to the same bearer and then deliver it to the UE.

At step 710, the gateway may map the SDF to the EPS bearer according tothe setting result determined at the above step 708.

Further, in an embodiment, the mapped bearer may include information onindicating the WLAN preference. Specifically, a WLAN preference propertymay be added, and this addition may be performed using an extension of aGTP-U header part.

According to an embodiment, steps 706 and 708 may be simultaneouslyperformed.

In an embodiment, in order for the PGW to set the WLAN preference basedon the UE location, the PGW should be able to know the UE location.

FIG. 8 illustrates a method for acquiring, at a PGW, locationinformation about a terminal according to an embodiment. Specifically,this embodiment shows a message flow in which the PGW receives a reporton the UE location from an MME.

In an embodiment, signals may be transmitted or received among amobility management entity (MME) 802, a serving gateway (SGW) 804, a PGW806, and a policy and charging rules function (PCRF) 808.

At step 810, the PCRF 808 may transmit a UE information change reportingrequest to the PGW 806.

At step 815, the PGW 806 may deliver the received UE information changereporting request to the SGW 804.

At step 820, the SGW 804 may deliver the received UE information changereporting request to the MME 802.

At step 825, the MME 802 may check information acquired on the basis ofthe report received in connection with UE attach or UE location change.

At step 830, the MME 802 may deliver UE location-related information tothe SGW 804. In an embodiment, the MME 802 may deliver, to the SGW 804,information including at least one of a E-UTRAN cell global identifier(ECGI), a tracking area identity (TAI), a routine area identity (RAI), aservice area identity (SAI), a location area identity (LAI), and a cellglobal identity (CGI).

At step 835, the SGW 804 may deliver the received UE location-relatedinformation to the PGW 806. In an embodiment, the PGW 806 may checkinformation related to the UE location and thereby, depending on the UElocation information, apply different traffic setting policies.Specifically, the PGW 806 may perform mapping based on the UE locationinformation when mapping the received IP flow to a specific bearer.

At step 840, the PGW 806 may deliver the received information to thePCRF 808.

FIG. 9 illustrates another method for acquiring, at a PGW, locationinformation about a terminal according to an embodiment. Specifically,this embodiment shows a message flow in a process of delivering UElocation information corresponding to a WLAN AP to a gateway node.

Referring to FIG. 9, signals may be transmitted or received among a WLAN902, a PGW 904, and a PCRE 906.

At step 910, the PCRF 906 may transmit a UE information change reportingrequest to the PGW 904. Specifically, the PCRF 906 may have a presetfunction of requesting or forcing the PGW 904 to subscribe to the UElocation information.

At step 915, the PGW 904 may deliver the received UE information changereporting request to the WLAN 902. Depending on embodiments, an entityto which the received UE information change reporting request istransmitted may be determined variably. For example, this request may bedeliver to at least one of the SGW and the WLAN 902.

At step 920, the WLAN 902 may acquire UE information on the basis of thereceived UE information change reporting request. Specifically, the WLAN902 may transmit a signal for identifying the UE location or determinethe UE location on the basis of the strength of a signal received fromthe UE. Additionally, in case of association or re-association of UE,the WLAN 902 may identify the UE location through information such as aservice set identity (SSID), a basic service set identity (BSSID), or ahomogenous extended service set identifier (HESSID).

At step 925, the WLAN 902 may deliver the UE location, together with anidentifier such as SSID, BSSID, or HESSID, to the PGW 904. In anembodiment, the WLAN 902 may also deliver an identifier for identifyingthe UE. This identifier may include a subscriber identifier.

At step 930, in case the PCRF 906 subscribes to the location informationreport, the PGW 904 may deliver the UE location to the PCRF 906.

As discussed heretofore, the PGW 906 may apply different traffic settingpolicies to traffic being transmitted on the basis of the acquired UElocation information.

For allowing the UE to be offered, through the WLAN, QoS being similarin level to that offered through the cellular, the eNB and the WLAN APare required to exchange information about which level of traffic isdesired or can be delivered. For this, the eNB and the WLAN AP need amethod for transmitting or receiving information. Therefore, anembodiment of this disclosure discloses a procedure in which the eNBchecks, through the UE, whether the WLAN AP can accept traffic to besteered by the cellular.

FIG. 10 illustrates a method for checking, at a base station, whether aWLAN accepts traffic. Specifically, in this disclosed procedure, the eNBchecks, via the UE, whether the WLAN can accept traffic or not. Althoughin this embodiment the eNB checks traffic acceptability of WLAN throughthe UE, it is alternatively possible to check traffic acceptability ofWLAN through the network including the PGW.

Referring to FIG. 10, in an embodiment, signals may be transmitted orreceived among UE 1002, an eNB 1004 (denoted by E-UTRAN), and a WLAN1006.

At step 1010, the eNB 1004 may determine, based on resource conditionsof the entire access network, whether to transfer all or part of trafficbeing exchanged with the UE 1002 to the WLAN. Specifically, when theload of the cellular network increases, the eNB 1004 may determine totransfer part of traffic to the WLAN. In an embodiment, a basic unit oftraffic transfer may be a bearer. In an embodiment, a bearer of the 3GPPcellular network has a QoS parameter (e.g., QCI) having to be satisfied.Therefore, in order to check whether the WLAL AP 1006 can accept abearer, there is a need to check whether the WLAN AP 1006 can satisfy aQoS parameter of a bearer. For this, at step 1010, the eNB 1004 mayconvert a 3GPP QCI value of a bearer to be transferred to the WLAN intoTSPEC (Traffic SPECification) which is a parameter defined in IEEE802.11 WLAN standard.

At step 1015, the eNB 1004 may deliver a traffic steering requestmessage to the UE 1002. In an embodiment, the traffic steering requestmessage may contain BSSID of a target WLAN AP and a TSPEC value of abearer to be transferred. Therefore, after checking whether to set aWLAN traffic stream supporting the QoS parameter with the WLAN AP 1006,the UE 1002 may report a checking result. Further, in an embodiment,information required in case of steering traffic at the SGW may becontained in the message transmitted at step 1015. Specifically, thismessage may contain information about a bearer or IP flow which is atarget of traffic steering. Also, this message may contain a TEID of theSGW required when the WLAN AP 1006 performs uplink transmission. Basedon this, the SGW may create a GTP tunnel with the WLAN for trafficsteering.

At step 1020, the UE 1002 may transmit, to the WLAN 1006, a message thatcontains part of information received from the eNB 1004. Specifically,the UE 1002 that receives the traffic steering request message maytransmit a message for creating a traffic stream with the WRAN AP 1006,based on TSPEC provided from the eNB 1004. In an embodiment, the abovemessage for creating a traffic stream may include an ADDTS requestmessage. Further, TSPEC contained in the ADDTS request message may havea TSPEC value of a bearer, created by the eNB 1004, to be transferred.

At step 1025, the UE 1002 may receive an ADDTS response messagetransmitted by the WLAN AP 1006. The ADDTS response message may containat least one of a status code, a TS delay, and a TSPEC. In anembodiment, a status code field indicates whether traffic stream isestablished, and a TS delay field may contain information related to aretrial time in case of failing to create a traffic stream at this time.A TSPEC field may contain a TSPEC value of a traffic stream createdactually. Additionally, in an embodiment, any information required whentraffic steering is performed at the SGW may be contained in a messagetransmitted at the above step 1025. Specifically, this message maycontain information about a bearer or IP flow which is a target oftraffic steering. Also, at least one of TEID and IP address of the WLANAP 1006 required when the WLAN AP 1006 performs downlink reception maybe contained.

At step 1030, the UE 1002 may transmit a response message to the eNB,based on the above field value delivered from the WLAN AP through theADDTS response.

At step 1035, the eNB 1004 may determine, based on the receivedinformation, whether to steer traffic. Specifically, the eNB maydetermine to transfer traffic when the WLAN 1006 can satisfy QoS oftraffic to be transferred. If the WLAN 1006 may not satisfy QoS, the eNBmay transfer other traffic capable of satisfying QoS. The order ofdetermining traffic that satisfies QoS may be from traffic having ahigher WLAN preference to traffic having a lower WLAN preference.

Although the eNB ascertains that the WLAN can accept traffic in anembodiment, the WLAN using an unlicensed band has always a possibilityof QoS degradation due to external interference or the like. Therefore,in another embodiment of this disclosure, a method for returning trafficto the cellular when QoS of the WLAN is degraded will be described.

FIG. 11 illustrates a method for returning, at the base station, traffictransmitted to a WLAN to a base station according to an embodiment.Specifically, shown is a message flow of a procedure in which the eNBreturns traffic, transferred to the WLAN, to the cellular.

Referring to FIG. 11, data may be transmitted or received among UE 1102,an eNB 1104 (denoted by E-UTRAN), and a WLAN 1106.

At step 1110, the eNB 1104 may transmit a WLAN traffic monitor controlmessage to the UE 1102. Specifically, the eNB 1104 may transmit, to theUE 1102, the WLAN traffic monitor control message that instructsmonitoring about traffic in order to check whether QoS of a bearertransferred to the WLAN 1106 is degraded

The WLAN traffic monitor control message may contain at least one of IDof a bearer as a monitoring target, a period to receive QoS statusmonitoring from the UE at the eNB, a report type, and a time to trigger.According to an embodiment, the report type may be set asEvent-Triggered. In this case, reporting is carried out only when anevent of QoS degradation happens, thus reducing message transmissionoverhead for reporting. Additionally, in order to prevent a temporaryQoS degradation from being reported to the eNB 1104, it may be set toreport a QoS degradation to the eNB 1104 only when the QoS degradationcontinues more than the time to trigger.

Further, in an embodiment, since the eNB 1104 may transfer one or morebearers to the WLAN, the WLAN traffic monitor control message maycontain one or more of the above parameter sets.

At step 1115, the UE 1102 may perform data communication with the WLANAP 1106. Specifically, the UE 1102 serves, through the WLAN AP 1106,traffic of a bearer steered to the WLAN AP 1106 from the cellular eNB.

At step 1120, the UE 1102 may monitor, based on at least one ofinformation received at step 1110, whether QoS of traffic is degraded.In order to differentially identify WLAN traffic corresponding to abearer, the UE 1102 may manage the bearer in response to a trafficstream. A method for setting a traffic stream may correspond to thatdescribed in another embodiment.

At step 1125, the UE 1102 may transmit a monitoring report to the eNB1104, based on the monitoring result and information received at step1110. The monitoring report may contain at least one of a bearer ID anda bearer status.

At step 1130, the eNB may determine, based on the received monitoringreport, whether to perform traffic steering. Specifically, in case QoSof a bearer transmitted by the WLAN AP is degraded, this bearer may besteered to be serviced by the eNB.

Further, in an embodiment of this disclosure, the eNB may determine totransfer a specific bearer from the cellular to the WLAN or vice versain view of resource conditions of the radio access network. A process ofresetting, at the eNB, a bearer among the UE, the access network, andthe core network gateway will be described.

FIG. 12 illustrates a method for transferring a bearer serviced by abase station to a WLAN according to an embodiment of this disclosure.Specifically, shown is a message flow initiated by the eNB andtransferring a cellular bearer to a WLAN bearer.

Referring to FIG. 12, signals may be transmitted or received among UE1201, eNB 1202, WLAN AP 1203, MME 1204, SGW 1205, PGW 1206, and PCRF1207.

At step 1210, the eNB 1202 may determine to serve at least one ofbearers, being serviced by the eNB 1202, through the WLAN 1203.Specifically, based on at least one of a resource condition of eachaccess network and features of a bearer, the eNB 1202 may determine toserve, through the WLAN 1203, a bearer which is served to the UE 1201through the cellular.

Therefore, the eNB 1202 may transmit, to the PGW 1206, a message forsteering downlink traffic toward the WLAN 1203. Also, the eNB 1202 maytransmit, to the UE 1202, a message for steering uplink traffic towardthe WLAN 1203.

At step 1215, the eNB 1202 may deliver the message for traffic steeringto the PGW 1206. Specifically, the eNB 1202 delivers a flow-to-bearermapping update message to the PGW 1206 (through the MME 1204 and the SGW1205). Also, if the SGW 1205 connects the eNB 1202 and the WLAN 1203,the message for traffic steering may be transmitted to the SGW 1206.

According to an embodiment, the flow-to-bearer mapping update messagemay contain an ID of a bearer to be transferred to the WLAN 1203 by theeNB 1202. Specifically, the ID of a bearer may be contained as a sourceEPS bearer ID parameter in this message. Also, this message may containan identifier indicating the WLAN 1203 to which a bearer will betransferred and serviced. This identifier indicating the WLAN includes aBSSID.

At step 1220, in case of a network that uses PCC (Policy and ChargingControl) infra, the PGW 1206 that receives the above message maydeliver, to the PCRF 1207, a bearer change request serviced through theeNB 1202, based on information contained in the received message.Specifically, this bearer change request may be performed through IP-CANsession modification. Therefore, the PCRF 1207 may deliver an updatedPCC decision to the PGW 1206.

At step 1225, the PGW 1206 may update a flow-bearer mapping relationsuch that a flow mapped to a bearer corresponding to a source EPS bearerID may be mapped to a WLAN bearer. Therefore, the PGW 1206 may steer thedownlink traffic from the cellular to the WLAN.

At step 1230, the PGW 1206 may transmit a response message to the eNB1202 (via the SGW 1205 and the MME 1204). Specifically, the PGW 1206 maytransmit, to the eNB 1202, a flow-to-bearer mapping update ack messageas a response to the flow-to-bearer mapping update message received atstep 1215. In an embodiment, this response message may contain at leastone of LIF (Logical Interface) table config and UL TFT (Traffic FlowTemplate) to be delivered again to the UE 1201 by the eNB 1202. Further,in case of a network using PCC infra, the LIF table config and the ULTFT may be values received by the PGW 1206 while a PCC decision of thePCRF 1207 is delivered.

At step 1235, the eNB 1202 may transmit a message to the UE 1201 suchthat uplink traffic can be steered to the WLAN. Specifically, the eNB1202 transmits a traffic steering command message comprising the LIFtable config and the UL TFT to the UE 1201 such that uplink traffic canbe steered from the cellular to the WLAN. A detailed process in whichtraffic in a bearer is steered from the cellular to the WLAN through theLIF table config and the UL TFT will be described below.

At step 1240, based on the received message, the UE 1201 may performtraffic steering to transmit specific traffic to the WLAN interface.Specifically, the UE 1201 may update a logical interface table and ULTFT, based on the LIF table config and the UL TFT in the trafficsteering command message received from the eNB 1202. Therefore, the UE1201 may transmit, to the WLAN interface, traffic desired to steer fromthe cellular to the WLAN by the eNB 1202.

At step 1245, the UE 1201 may transmit, to the eNB 1202, a message fornotifying that traffic steering is completed.

In an embodiment, traffic of a cellular bearer sent to the WLAN 1203 maybe transmitted between the UE 1201 and the WLAN access through WLANconnectivity. There is a need to set which bearer will deliver trafficin a section between the WLAN access 1203 and the PGW 1206.

At step 1250, the PGW 1206 may deliver an update bearer request messagefor a bearer update to the WLAN access 1203. In an embodiment, theupdate bearer request message may contain at least one of an EPS bearerID and EPS bearer QoS information required for a bearer update. Also,the update bearer request message may contain UL TFT informationrequired for mapping traffic, delivered through WLAN connectivity, to aspecific bearer at the WLAN access 1203.

At step 1255, the WLAN 1203 may map an uplink flow to a specific bearer,based on the received message.

At step 1260, the WLAN 1203 may transmit a response message to the PGW1206. This response message may contain an update bearer response, whichmay contain an updated EPS bearer ID.

In an embodiment, steps 1235 to 1245 and steps 1250 to 1260 may beperformed regardless of the order of operation and may be performedsimultaneously.

FIG. 13 illustrates a method for steering traffic at a terminalaccording to an embodiment. Specifically, shown are configurationexamples of a protocol stack including a logical interface in UE, alogical IF table, and a UL TFT.

Referring to FIG. 13, an upper layer above an IP layer creates five IPflows including Flow to Flow 5. Also, the IP layer 1302 may transmitdownwards these five IP flows to a logical interface 1304.

In an embodiment, the logical interface 1304 may process the IP flows,based on the logical interface table. The logical interface tablecontains a mapping ID 1312 for each flow and may have a flow description1314 formed of 5-Tuple (a source IP address, a destination IP address, asource port number, a destination port number, and a protocolidentifier) in a similar manner to a filter rule in FIG. 6. Also, basedon the flow description 1314, a physical interface 1316 may bedetermined.

Further, the logical interface table has a function to deliver trafficmapped to the flow description 1314 to the corresponding physicalinterface 1316. In an embodiment, the physical interface 1316 mayinclude an LTE interface 1306 and a WLAN interface 1308. For example, inthe configuration example of the logical interface table, the first rowindicates that an IP flow corresponding to (*, UE IP, SIP, *, UDP) issent to the LTE interface. This flow sent to the LTE interface undergoesagain filtering of the UL TFT 1320 within the LTE interface. In anembodiment, the configuration of the UL TFT 1320 may include a flowdescription 1322 and a corresponding bearer ID 1324. According to theconfiguration example of the UL TFT 1320, the above flow correspondingto (*, UE IP, SIP, *, UDP) will be mapped to Bearer 1 and delivered tothe eNB.

The logical interface table and the LTE UL TFT may be determineddepending on a preset value or on the basis of a signal received fromthe eNB.

Further, according to an embodiment, the LTE interface 1306 and the WLANinterface 1308 may be implemented in the same chip. In this case, theLTE interface 1306 and the WLAN interface 1308 may be located below theIP layer 1302 without the logical interface 1304, and also the UL TFT1320 may filter the entire information transmitted or received betweenthe LTE interface 1306 and the WLAN interface 1308. Through this, a WLANsteering may be performed much more smoothly.

FIG. 14 illustrates a method for transferring a bearer serviced by aWLAN to a base station according to an embodiment of this disclosure.Specifically, the flow of message transferring a bearer via WLAN to abase station in order to pass through a cellular network is shown.

Referring to FIG. 14, signals may be transmitted or received among UE1401, eNB 1402, WLAN AP 1403, MME 1404, SGW 1405, PGW 1406, and PCRF1407.

At step 1410, the eNB 1402 may determine to service, through the eNB1402, at least one of bearers serviced the by WLAN 1403. Specifically,based on at least one of a resource condition of each access network anda feature of a serviced bearer, or based on a QoS monitoring result of abearer transferred to the WLAN, the eNB 1402 may determine to service,through the cellular again, the bearer steered to the WLAN.

Therefore, the eNB 1402 may transmit, to the PGW 1406, a message forsteering downlink traffic of the bearer toward the eNB 1402. Also, theeNB 1402 may transmit, to the UE 1401, a message for instructing totransmit uplink traffic toward the eNB 1402.

At step 1415, the eNB 1402 may deliver a message for traffic steering tothe PGW 1406. Specifically, the eNB 1402 delivers a flow-to-bearermapping update message to the PGW 1405 (via the MME 1404 and the SGW1405).

According to an embodiment, the flow-to-bearer mapping update messagemay contain an ID of a bearer to be transferred to the cellular networkby the eNB 1202. Specifically, the ID of a bearer may be contained as asource EPS bearer ID parameter in this message. Specifically, accordingan embodiment, the ID of the bearer may include the ID of an originalbearer, which is set primarily to go via the cellular network andsteered to go via the WLAN by the decision of the eNB, not the ID of abearer which is set currently to go via the WLAN.

At step 1420, in case of a network that uses PCC (Policy and ChargingControl) infra, the PGW 1406 that receives the above message maydeliver, to the PCRF 1407, a bearer change request of the eNB 1402. Thenthe PCRF 1407 may deliver an updated PCC decision to the PGW 1406.

At step 1425, the PGW 1406 may update a flow-bearer mapping relationsuch that a flow indicated by a source EPS bearer ID may be mapped to acellular bearer. In an embodiment, if a bearer having the source EPSbearer ID is released, the PGW 1406 may reset the released bearer.Therefore, downlink traffic may be steered from the WLAN 1403 to thecellular network of the eNB 1402.

At step 1430, the PGW transmits a flow-to-bearer mapping update ackmessage as a report about the flow-to-bearer mapping update message tothe eNB (via the SGW 1405 and the MME 1404). This message may contain,as parameters, LIF (Logical Interface) table config and UL TFT to bedelivered again to the UE by the eNB. In case of a network using PCCinfra, the LIF table config and the UL TFT may be values received whilea PCC decision of the PCRF is delivered.

At step 1435, the eNB 1402 may transmit a message to the UE 1401 suchthat uplink traffic can be steered from the WLAN 1403 to the cellularnetwork of the eNB 1402. Specifically, the eNB 1402 may transmit atraffic steering command message comprising the LIF table config and theUL TFT to the UE 1401 and thereby instruct to steer uplink traffic fromthe WLAN to the cellular network of the eNB 1402.

At step 1440, the UE 1401 that receives the LIF table config and the ULTFT in the traffic steering command message may update the receivedinformation in a logical interface table and UL TFT. Therefore, trafficdesired by the eNB 1402 to steer from the WLAN 1403 to the cellularnetwork of the eNB 1402 may be transmitted toward the cellular interfaceand mapped to a bearer by UL TFT within the cellular interface of theeNB 1402.

Meanwhile, in an embodiment, although a rule regarding the steeredtraffic of UL TFT which is set to the WLAN access 1403 is not needed anymore, there is a need to synchronize and maintain the content of UL TFTin the PGW 1406 and the WLAN access 1403. Also, there may be a need tochange setting of a bearer since traffic delivered between the WLAN 1403and the PGW 1406 is decreased.

Therefore, at step 1450, the PGW 1406 may deliver an update bearerrequest message to the WLAN access 1403. This message may contain an EPSbearer ID and EPS bearer QoS information required for a bearer update.Also, information on updating UL TFT which is set to the WLAN access maybe contained.

At step 1455, the WLAN 1403 may update a bearer, based on the receivedinformation.

At step 1460, the WLAN 1403 may transmit a response message to the PGW1406. In an embodiment, this response message may contain a bearer ID.In an embodiment, in case of determining to service, through the eNB1402, one or more of a plurality of bearers serviced by the WLAN 1403,one or more of such bearers may be selected to be serviced through theeNB 1402, based on a WLAN preference value. Specifically, it isdetermined to service a bearer having a low WLAN preference valuethrough the eNB 1402.

FIG. 15 is a diagram illustrating a terminal according to an embodiment.

Referring to FIG. 15, UE in an embodiment may include a transceiver unit1510 capable of transmitting or receiving a signal to or from at leastone of eNB and WLAN.

Also, a UE control unit 1520 controls the transceiver unit 1510 totransmit or receive a signal and may process the signal and control thewhole operation of the UE 1500. Specifically, the UE control unit 1520in an embodiment may perform association or re-association with theWLAN. Also, the UE control unit may transmit information related to theUE location to the eNB or perform attach. Also, the UE control unit maydetermine the status of the WLAN, based on information received from theeNB, and deliver it to the eNB. Also, the UE control unit may monitorQoS of traffic serviced by the WLAN and then deliver it to the eNB.Also, the UE control unit may steer traffic serviced by the eNB or theWLAN to the WLAN or the eNB in response to instructions of the eNB.Also, the UE control unit may map each IP flow to the cellular IF or theWLAN IF according to specific setting. Additionally, the UE control unit1520 may control the overall operations of the UE disclosed inembodiments of this disclosure.

Further, the UE 1500 may include a memory unit 1530 for storing a signaltransmitted or received via the transceiver unit 1510 and/or informationrelated to a signal processed by the control unit 1520.

FIG. 16 is a diagram illustrating a WLAN according to an embodiment.

Referring to FIG. 16, the WLAN 1600 in an embodiment may include atransceiver unit 1610 capable of transmitting or receiving a signal toor from at least one of UE and PGW.

Also, a WLAN control unit 1620 controls the transceiver unit 1610 totransmit or receive a signal and may process the signal and control thewhole operation of the WLAN 1600. Specifically, the WLAN control unit1620 in an embodiment may perform association or re-association with theUE. Also, the WLAN control unit may receive, from the PGW or the UE, atraffic steering signal triggered by the eNB and then perform a relatedoperation. Also, the WLAN control unit may deliver a traffic state ofthe WLAN to the UE. Also, the WLAN control unit may deliver, to the UE,information related to QoS of traffic serviced by the WLAN.Additionally, the WLAN control unit 1620 may control the overalloperations of the UE disclosed in embodiments of this disclosure.

Further, the WLAN 1600 may include a memory unit 1630 for storing asignal transmitted or received through the transceiver unit 1610 and/orinformation related to a signal processed by the control unit 1620.

FIG. 17 is a diagram illustrating a base station according to anembodiment.

Referring to FIG. 17, eNB 1700 in an embodiment may include atransceiver unit 1710 capable of transmitting or receiving a signal toor from at least one of UE and a network node. In an embodiment, thenetwork node may include MME, SGW and PGW.

Also, an eNB control unit 1720 controls the transceiver unit 1710 totransmit or receive a signal and may process the signal and control thewhole operation of the eNB 1700. Specifically, the eNB control unit 1720in an embodiment may determine whether to steer traffic, based oncommunication conditions and WLAN preference information of a bearerreceived from the PGW. In case traffic steering is determined, the eNBcontrol unit may deliver a message for traffic steering to the UE andthe PGW. Also, the eNB control unit may deliver a signal for monitoringa WLAN status and a status of a bearer transmitted by the WLAN.Additionally, the eNB control unit 1720 may control the overalloperations of the UE disclosed in embodiments of this disclosure.

Further, the eNB 1700 may include a memory unit 1730 for storing asignal transmitted or received through the transceiver unit 1710 and/orinformation related to a signal processed by the control unit 1720.

FIG. 18 is a diagram illustrating a PGW according to an embodiment.

Referring to FIG. 18, PGW 1800 in an embodiment may include atransceiver unit 1810 capable of transmitting or receiving a signal toor from a network node. In an embodiment, the network node may includeeNB, MME, SGW, PGW, and PCRF.

Also, a PGW control unit 1820 controls the transceiver unit 1810 totransmit or receive a signal and may process the signal and control thewhole operation of the PGW 1800. Specifically, the PGW control unit 1820in an embodiment may perform steering of downlink data, based on asignal received from the eNB. Specifically, based on informationreceived from the eNB, the PGW control unit may steer traffic, beingtransmitted through the eNB, to the WLAN, or traffic, being transmittedthrough the WLAN, to the eNB. Also, the PGW control unit may classifyreceived flows, based on their features, and map each flow to a specificbearer. Also, the PGW control unit may allow a WLAN preference fordetermining steering according to features of IP flow including abearer. Additionally, the PGW control unit 1820 may control the overalloperations of the UE disclosed in embodiments of this disclosure.

Further, the PGW 1800 may include a memory unit 1830 for storing asignal transmitted or received through the transceiver unit 1810 and/orinformation related to a signal processed by the control unit 1820.

While this invention has been particularly shown and described withreference to an exemplary embodiment thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of thisinvention as defined by the appended claims.

What is claimed is:
 1. A method of transmitting a signal by a terminalin a wireless communication system, the method comprising: identifying amapping identifier (ID) for a packet flow; mapping the packet flow to aphysical interface based on the mapping ID, wherein the physicalinterface includes a long term evolution (LTE) interface and a wirelesslocal access network (WLAN) interface; mapping the packet flow to a dataradio bearer (DRB) based on a flow description corresponding to themapping ID, in case that a physical layer to be mapped with the packetflow is the LTE interface, by a layer between the packet flow and apacket data convergence protocol (PDCP) layer of the terminal; andtransmitting, to a base station, the packet flow on the DRB, wherein theDRB is determined based on a mapping rule between the packet flow andthe DRB, in case that the mapping rule is received from the basestation, and wherein the DRB is determined as a default DRB, in casethat the mapping rule between the packet flow and the DRB is notreceived from the base station.
 2. The method of claim 1, wherein themapping rule configures at least one identifiers of a packet flow whichis mapped to the DRB.
 3. A terminal of transmitting a signal in awireless communication system, the terminal comprising: a transceiverconfigured to transmit and receive a signal; and a controller configuredto: identify a mapping identifier (ID) for a packet flow, map the packetflow to a physical interface based on the mapping ID, wherein thephysical interface includes a long term evolution (LTE) interface and awireless local access network (WLAN) interface, map the packet flow to adata radio bearer (DRB) based on a flow description corresponding to themapping ID, in case that a physical layer to be mapped with the packetflow is the LTE interface, by a layer between the packet flow and apacket data convergence protocol (PDCP) layer of the terminal, andcontrol the transceiver to transmit, to a base station, the packet flowon the DRB, wherein the DRB is determined based on a mapping rulebetween the packet flow and the DRB, in case that the mapping rule isreceived from the base station, and wherein the DRB is determined as adefault DRB, in case that the mapping rule between the packet flow andthe DRB is not received from the base station.
 4. The terminal of claim3, wherein the mapping rule configures at least one identifiers of apacket flow which is mapped to the DRB.